Unity - Play Maker programmer

I have a small project going on, using Unity Pro 4.5 and Play Maker. The aim of the project is to demo how the sun will light and shade the building during the day. If you check the attached file, (unity executable for Mac and windows 64 bit) you'll see a slider in the scene that controls the sun light direction and shadows. The slider only controls the sun direction, but I would like to control the sun color and the sky color (camera background color atm). The sun and sky will go from a blueish color at morning, then to light yellow at mid day and finally orangeish at noon, should be a smooth transition between them. The service provider should have Play Maker skills, all coding should run under Play Maker. The goal of this project is to control the sun color and sky color with the existing slider that controls the sun direction.